Not applicable.
Not applicable.
This invention is in the field of data communications, and is more particularly directed to the architecture, operation, and control of access multiplexers for effecting such communications.
In recent years, the data rates at which communications are carried out over conventional telephone networks and wiring have greatly increased. These increases are due, in large part, to newly adopted techniques of multiplexing and modulating signals representative of the messages or data being communicated, resulting in greatly improved communication bandwidth. In addition, the carrier frequencies at which such communications are being carried out have also increased in recent years, further improving the bit rate.
These higher data rates are achieved in one relatively new type of current modem communications technology, referred to in the art as digital subscriber line (xe2x80x9cDSLxe2x80x9d). DSL refers generically to a public network technology that delivers relatively high bandwidth over conventional telephone company copper wiring, generally at limited distances. DSL has been further separated into several different categories of technologies according to specific expected data transfer rates, the types and lengths of the medium over which data are communicated, and schemes for encoding and decoding the communicated data. According to this technology, data rates between DSL modems may be far greater than current voice modem rates. Indeed, current DSL systems operate (or are projected to operate) at data rates ranging from on the order of 500 Kbps to 18 Mbps or higher. According to certain conventional techniques, such as the protocol referred to as Asymmetric Digital Subscriber Line (ADSL) and which corresponds to ANSI standard T1.413, the data communication rates are asymmetrical. Typically, the higher rate is provided for so-called downstream communications, that is from the telephone network central office to the customer modem, with upstream communication from the customer modem to the central office having a data rate considerably lower than the downstream rate.
An integral part of a DSL communications network is referred to in the art as the Digital Subscriber Line Access Multiplexer, or xe2x80x9cDSLAMxe2x80x9d. DSLAMs are typically located at a central office of the telephone network, and include multiple DSL modem ports into which client modems may connect. The primary function of a DSLAM is to multiplex client data communications from its multiple DSL modem ports into a network, such as a local area network (LAN) which may include a server and an Internet gateway; return data communications from the network are also demultiplexed by the DSLAM for communication to the clients via the DSL ports.
Conventional DSLAMs are typically realized by way of multiple line cards, each of which supports one or more DSL ports. The communications received at the DSL ports are typically in packet form, each having headers or tails (or both) containing the appropriate routing information for the packet message. A DSLAM controller function performs the appropriate framing and data formatting by way of which the packets received at the DSL ports are conveyed, according to the appropriate protocols, to a network interface card (NIC) in the DSLAM and thus to the network. In general, conventional DSLAMs modulate and demodulate multiple DSL channels corresponding to multiple client locations, effect line concentration in the communications network, provide an interface to the communications network, and provide management of the communications system.
These important functions provided by DSLAMs in a communications network, particularly in a DSL environment, are relatively complex in nature, especially considering the high data rate communications that are supported. The design and realization of a DSLAM has therefore been relatively complex, particularly in terms of system analysis and debugging.
Furthermore, considering the line concentration function performed thereat, a typical DSLAM has access to the operating characteristics of many DSL channels, as well as bidirectional access to client modems. Heretofore, this access has not been fully utilized in the management and operation of the communications network.
It is therefore an object of the present invention to provide a DSLAM having sufficient processing capability to effect element management system (EMS) functionality relative to multiple communications channels.
It is a further object of the present invention to provide such a DSLAM in which such a management system may be effected both locally, by a host computer coupled to the DSLAM, and also remotely by way of a network.
It is a further object of the present invention to provide such a DSLAM in which debugging of the DSLAM and its operation is facilitated by way of interface of a local host computer to the DSLAM.
It is a further object of the present invention to provide such a DSLAM that can update the operating software of client modems, under the control of a host computer or a network-linked computer.
Other objects and advantages of the present invention will be apparent to those of ordinary skill in the art having reference to the following specification together with its drawings.
The present invention may be implemented by way of a digital subscriber line access multiplexer (DSLAM), preferably implemented by way of digital signal processors (DSPs), and having an element management system agent operable thereupon. The element management system agent interfaces with a host computer, for example by way of a high speed serial interface, by way of which debugging, system management, user control, and other operations may be carried out upon the DSLAM.
According to another aspect of the present invention, the DSLAM includes a network interface agent, by way of which other computers, for example computers on a local area network with the DSLAM, may access and operate the element management system of the DSLAM, such that system management, user control, and other system functions may be initiated remotely for execution at the DSLAM.